In the related art, a heat storage board which is used as a wall material for a house or the like is known (for example, NPL 1). The heat storage board includes a plate-like heat insulation member, and a plurality of microcapsules which is contained in the heat insulation member, and is sealed with a latent heat storage material. A phase change temperature of the latent heat storage material is approximately 23° C. or 26° C.